Debarking machine

ABSTRACT

A DEBARKING MACHINE OF THE HOLLOW HEAD TYPE WHICH TRANSFERS LOSS ALONG A PRESCRIBED PATH WHILE PROGRESSIVELY REMOVING THE BARK THEREFROM BY A PLURALITY OF DEBARKING TOLLS WHICH ARE ROTATED CIRCUMFERENTIALLY ABOUT THE LOG BY A ROTATABLE TOOL HOLDER. THE LOGS ARE DRIVEN BY A PLURALITY OF FEED ROLLS, EACH FEED ROLL INCLUDING AN ELECTRICAL DRIVING MOTOR HOUSED THEREIN, AND THE DEBARKING TOLLS ARE FORCED AGAINST THE LOG PASSING THEREBY BY FLUID CYLINDERS SUPPLIED WITH FLUID UNDER PRESSURE FROM A PLURALITY OF FLUID PRESSURE PUMPS CARRIED BY THE TOOL HOLDER AND ACTIVATED BY A PUMPING CAM AS THE TOOL HOLDER IS ROTATED.

United States Patent lnventors Thomas P. Bush, Jr.

133 Red Oak Road. Birmingham, Ala.

35206; Samuel E. Grant, 20 l-loneybrook Drive, Jacksonville, Fla. Appl. No. 765,388 Filed Oct. 7, 1968 Patented June 28, 1971 DEBARKING MACHINE 9 Claims, 7 Drawing Figs.

U.S. C1. 144/208 Int. Cl B271 1/00 Field of Search 144/208 References Cited UNITED STATES PATENTS 8/1962 Marble et a1 144/208 3,333,615 8/1967 Robbins Primary Examiner- Donald R Schran Attorney- Newton, Hopkins and Ormsby ABSTRACT: A debarking machine of the hollow head type which transfers logs along a prescribed path while progressively removing the bark therefrom by a plurality of debarking tools which are rotated circumferentially about the log by a rotatable tool holder. The logs are driven by a plurality of feed rolls, each feed roll including an electrical driving motor housed therein, and the debarking tools are forced against the log passing thereby by fluid cylinders supplied with fluid under pressure from a plurality of fluid pressure pumps carried by the tool holder and activated by a pumping cam as the tool holder is rotated.

PATENTEU JUN28 I97I SHEET 3 UF 4 INVE N T 0R3 THOMAS P BUS/(JR SAMUEL E. GRANT 1 4 TTOENEY DEBARKING MACHINE BACKGROUND OF INVENTION 1. Field of Invention This invention relates generally to a debarking machine for removing the bark from logs and is more particularlyconcerned with a debarking machine which feeds the log to be debarked along a prescribed path and which circumferentially and progressively removes the bark therefrom as the logs pass along this prescribed path.

2. Description of the Prior Art Debarking machines for removing the bark from logs for sawmills and wood pulp industries are well known in the prior art, one common type of these debarking machines being the hollow head type. In this type of machine, logs having the bark thereon are moved along a prescribed straight path by a first plurality of driven feed rolls as the logs pass into the machine and are maintained centered as they pass from the machine by a second plurality of feed rolls. As the logs pass from the first feed rolls to the second feed rolls, they pass a plurality of debarking tools. The debarking tools are pivotally arranged in a rotatable tool holder surrounding the logs and are pressed against the logs with such force that the bark is removed from the logs as the tool holder is rotated thereabout carrying the debarking tools therewith.

Prior art debarking machines normally use an elastic band to press the debarking tools against the log for removing the bark therefrom. One of the problems with using elastic bands to supply the force to hold the debarking tools against the logs is the fact that the elastic bands frequently break or lose their elastic properties, thereby increasing the cost of maintenance of the machine as well as decreasing the overall production efficiency of the machine. Another disadvantage with this particular type of arrangement is that the tension of the elastic bands can only be changed by stopping the machine and regulating a spider which carries the elastic. bands within the rotatable tool holder. This has resulted in greatly increasing the amount of nonproductive time required to effectively set up a log debarking operation or to readjust the log debarking operation for'different size logs.

SUMMARY OF INVENTION The invention disclosed herein overcomes these and other problems associated with prior art debarking machines by providing a pressure means which will force the debarking tools against the logs at the same pressure regardless of the diameter of the log being debarked. Moreover, the pressure means can be regulated to change the pressure at which the tools are forced against the log even while the machine is operating. Therefore, not only can many different sizes of trees be debarked without having to stop the operation of the machine, but also different species of logs may be debarked without having to stop the operation of the machine for setup.

The apparatus of the invention includes a support frame which rotatably mounts an annular tool holder that is rotated by a drive motor through a drive mechanism. A plurality ofdebarking tools are pivotally carried by the tool holder and rotate therewith as the tool holder is rotated by the drive motor. Fluid cylinder means is provided in the tool holder for selectively pivoting the debarking tools with respect to the tool holder as the tool holder is rotated. Fluid under pressure is supplied to the cylinder means by a plurality of fluid pumps circumferentially spaced about the tool holder. These fluid pumps are activated by a pump cam pivotally mounted in the support frame. The pump cam is selectively positioned so that, by selectively pivoting the pump cam, the amount of fluid pumped can be selectively maintained, thereby selectively regulating the pressure exerted on the debarking tools to debark a tree.

To further control the pressure of the fluid supplied to the fluid cylinders, a pressure regulating means is operatively connected thereto. The pressure regulating means is carried within the tool holder but can be selectively controlled externally of the machine while it is operating to selectively control the pressure of the fluid supplied to the fluid cylinders. Thus, not only can the pump cam be utilized to control the pressure of the fluid being supplied to the fluid cylinders, but the regulating means may also-be used to further provide accurate control of the pressure of the fluid.

The apparatus of the invention also includes a plurality of feed rolls which are pivotally carried by the support frame and rotatable about an axis perpendicular to the prescribed path along which the logs pass. Each corresponding front and back feed rolls are pivoted and fluid cylinders to be forced against a 4 log to be debarked and maintain the log centered along the prescribed path for passage through the debarking machine. The feed rolls are selectively driven bya small motor carried in each of the feed rolls. Since these motors can be operated at substantially constant speed, they are effective to drive all the feed rolls at a substantially constant speed all of the time, even though the relative pivotal positions of the feed rolls may vary.

These and other features and advantages of the invention will be more clearly understood upon consideration of the following detailed description and the accompanying drawings wherein like characters, of reference designate corresponding parts throughout and in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of one embodiment of the invention; I

FIG. 2 is a front plan view ofthe invention shown in FIG. 1;

FIG. 3 is an enlarged front plan view of the tool holder of the invention shown in FIG. 1 with portions thereof broken away to show the interior construction thereof;

FIG. 4 is a side elevational view of the tool holder shown in FIG. 3 with portions thereof broken away to show the-interior construction thereof;

FIG. 5 is a schematic wiring'diagram to operate the inventlon;

FIG. 6 is an enlarged perspective view of the debarking tool pivoting mechanism of the invention; and

FIG. 7 is an enlarged detailed side view of the pressure regulating valve of the invention partially broken away to show the interior construction thereof;

These FIGS. and the following specification disclose specific embodiments of the invention; howeyer, the inventive concept is not limited thereto since it may be embodied in other equivalent forms. I

DESCRIPTION OF IIQLUSTRATIVE EMBODIMENTS Referring to FIGS. 1 and 2, it will be seen that the invention comprises generally a frame 10 which rotatably mounts an annular tool holder 11 therein. An entry feed roll assembly 12 is mounted in front of the tool holder 11 and an exit roll assembly 13 is mounted in back of the tool holder 11. It will be seen that the log L having bark thereon is fed into the machine, from the right side thereof as seen in FIG. 1 and from the near side thereof as seen in FIG. 2, along a prescribed path P; travels through the machine without appreciably turning about its longitudinal axis as the bark is removed therefrom; and subsequently travels out of the machine on the left side thereof as seen in FIG. 1 and on the far side thereof as seen in FIG. 2.

The frame 10 is of a rectangular configuration and comprises a pair of spaced vertical side plates 14 joined together by a front plate 15 and a back plate 16. The construction of the frame 10 is completed by a top plate 18 and a bottom plate 19 joining the side plates 14 and thefront and back plates 15 and 16 to form a tool cavity C in the frame 10. The front and back plates 15 and 16 define large apertures 20 and 21 respectively therethrough, as best seen in FIG. 4, which are aligned with each other and concentric about the prescribed pathP.

Fixedly mounted inside the frame 10 on the rear side of the front plate 15 is an annular outer bearing race 22. The race 22 rotatably mounts the annular tool holder 11 in the cavity C about the prescribed path P by an annular inner race 24 affixed to the annular tool holder 11 and a plurality of ball bearings 25 which rotatably fit within the outer race 22 and the inner race 24. The outer race 22 is of conventional split construction to facilitate mounting of the tool holder 1 I.

The annular tool holder 11 is defined by inner and outer spacer rings 26 and 28 which are concentrically located with respect to each other and with respect to the prescribed path P by a front annular support plate 29 and a rear annular support plate 30. The front support plate 29 and the rear support plate 30 define a large aperture therethrough having the same diameter as the inner spacer ring 26 to permit the logs L to pass therethrough along the prescribed path P. The rear support plate 30 has an outside diameter which is equal to the outside diameter of the outer spacer 28 and the front support plate 29 has an outside diameter larger than the outside diameter of the outer spacer ring 28. That portion of the plate 29 extending past the ring 28 fixedly mounts the inner bearing race 24 thereto through bolts 31.

A large annular multigroove drive sheave 32 is affixed to the rear side of the tool holder 11 and is connected to a drive motor 34 through a plurality of V-belts 35 and an appropriate pulley (FIG. 1) attached to the drive shaft of the motor 34. Therefore, it will be seen that the drive motor 34 selectively rotates the tool holder 11 by rotating the V-belts 35.

Equally spacedcircumferentially about the tool holder 11 are a plurality of apertured bearing bosses mounted in and centered over aligned apertures in the plates 29 and 30. These bearing bosses 40 pivotally mount a plurality of tool carrier shafts 41 which have a debarking tool 42 of conventional design fixedly mounted on the end of each of the shafts 41 extending forwardly of the tool holder 11. These tools 42 pivot in a plane substantially perpendicular to the prescribed path P. A tool control mechanism 44 is carried by each of the tool carrier shafts 41 on the inside of the tool holder 11 and is effective to selectively position the tools 42 with respect to the center line of the tool holder 11 which coincides with the path P.

The tool control mechanisms 44, as seen in FIG. 6, include a pair of pivoting links 45 rotatably mounted at one end thereof about the shaft 41 and a cylinder support link 46 pivotally mounted between the other ends oflinks 45. The cylinder support link 46 fixedly carries a fluid cylinder 48 which has its piston rod 49 slidably extending through the support link 46 toward the shaft 41. Fixedly mounted to the shaft 41 between the pivoting links 45 is a connector 50 which is fixedly connected to the shaft 41 at one end thereof and which is pivotally connected to the piston rod 49 of the cylinder 48 at the other end thereof through a pinned joint .1. Therefore, it can be seen that the position of the shafts 41 can be selectively determined by extending and retracting the piston rod 49 of the fluid cylinder 48, thereby changing the relative position of the debarking tool 42 with respect to the prescribed path P. To prevent overextension of the piston rod 49 and the debarking tools 42, a stop 51, as seen in FIG. 3, is carried by the outer spacer ring 26 adjacent each of the shafts 41. The stops 51 are abutted by the connectors 50 at the extension limit of the piston rods 49.

An annular manifold 52, as best seen in FIG. 4, is fixedly mounted within the tool holder 11 and is connected to each of the fluid cylinders 48 so that fluid supplied thereto under pressure will be supplied to the fluid cylinders 48 to cause extension of the piston rods 49 and cause the debarking tools 42 to be pivoted toward the prescribed path P. A plurality of fluid pumps 54, as seen in FIG. 3, of conventional design are fixedly carried by the outer s acer ring 28 and are connected to the manifold 52 through check valves so that when the fluid pumps 54 are activated, they will supply fluid to the manifold 52, yet the check valves 55 will prevent escape of the fluid from the manifold 52 on the return stroke of the fluid pumps 54. Each pump 54 has a drive plunger 56 extending through the outer support ring 28 so that depression of the drive plunger 56 causes the pumps 54 to pump fluid under pressure into the manifold 52 and thus cause the cylinders 48 to extend their piston rods 49 and pivot the debarking tools 42 toward the prescribed path P. The plungers 56 are urged outwardly at all times by centrifugal force or by a resilient member to return the plungers 56 after each pumping stroke.

An arcuate pump cam 58, as seen in FIG. 3, is pivotally carried within the support frame 10 and is activated through a positioning mechanism 59, as seen in FIG. 2, such as a fluid cylinder, so that the cam 58 may be selectively moved toward and away from the outer spacer ring 28. The cam 58 encompasses approximately 90 of the circumference of the tool holder 11 and defines an inner camming surface 60 which will engage the plungers 56 of the pumps 54 and drive the plungers 56 inwardly so as to pump fluid into the manifold 52 as the tool holder 11 rotates the plungers 56 thereby. The control mechanism 59 may be selectively varied externally of the machine in known manner to vary the position of the cam 58 and change the pumping stroke of the plungers 56 thereby regulating the amount of fluid that will be pumped into the manifold 52 as the fluid pump 54 is rotated with the tool holder 11.

For further or alternately controlling fluid pressure within the manifold 52, a pressure regulating assembly 61, as seen in FIG. 7, is connected to the manifold 52 and includes a valve body 62 having a ball check 64 therein which is urged against a valve seat 65 within the valve body 62 by a spring 66 mounted within the valve body 62. The tension in the spring 66 can be selectively varied by moving the force plate 68 slidably carried within the housing 62. The plate 68 is mounted on the end of a selectively extendable solenoid core 69 of solenoid 70. Therefore, it will be seen that as the force plate is urged toward the ball check 64, the pressure that will be maintained within the manifold 52 will be higher than if the force plate 68 is moved away from the ball check 64.

The solenoid 70 is electrically connected to a control circuit C through a plurality of contact rings 71 and wiping contacts 72. The contact rings 71 are fixedly mounted within the support frame 10 and the wiping contacts 72 are carried by the tool holder II in conventional manner, the contact rings 70 and the wiping contacts 72 being of conventional design and readily available on the market.

Referring to FIG. 5, it will be seen that the control circuit C which is associated with the solenoid 70 has a common ground wire 100 and a common hot wire 101. The solenoid 70 is selectively connected between the wires 100 and 101 through a selectively variable current device 73. When the adjustment dial D is appropriately manipulated, the output current to the solenoid 70 is increased so that more force is exerted on the core 69 to compress the spring 66, and when the dialD is appropriately manipulated in the opposite direction, the force on the core 69 will be decreased so as to reduce the compression of the spring 66. In this manner, the pressure within the manifold 52 can be selectively and accurately controlled, even while the machine is being operated. By approximately marking the dial D in pounds of pressure, the pressure within the manifold 52 can be maintained at any desired pressure. It is to be understood, however, that other means may be utilized to operate the force plate 68.

Referring to FIGS. 1 and 2, it will be seen that the feed roll assemblies 12 and 13 are identical. Therefore, only the feed roll assembly 12 will be described in detail with primes of the reference members applied to the assembly 12 indicating corresponding parts of the assembly 13.

The entry feed roll assembly 12 includes a carriage having a pair of spaced uprights 81 joined at their lower ends by a base 82 and at their upper ends by an upper bearing beam 84 to define a hollow rectangular configuration. An intermediate bearing beam 85 spaced below beam 84 and parallel thereto extends between the uprights 81.

The upper bearing beam 84 carries an upper feed roll unit 86 and the intermediate bearing beam 85 carries a lower feed roll unit 88. The upper unit 86 comprises a motor support arm 89 pivoted at one end between bearing blocks 90 mounted on the underside of the beam 84. The extending end of the arm 89 rotatably mounts one end of an upper, horizontally orientated, feed roll 91 and also mounts a drive motor 92 on the interior of the feed roll 91 as best seen in FIG. 2. The drive shaft 94 of the motor 92 drivingly carries the opposite end of the roll 91. Therefore, it will be seen that the motor 92 will rotate the roll 91 about a horizontally disposed axis even though the arm 89 is pivoted with respect to the beam 84 and the path P.

The lower feed roll unit 88 is similar in construction to the unit 86, and comprises a motor support arm 95 pivoted at one end between bearing blocks 96 mounted on the intermediate beam 85. The arm 95 is in vertical alignment with the arm 89. The extending end of the arm 95 mounts a lower horizontally oriented feed roll 98 and motor 99, as does the arm 89. The drive shaft 100 of-motor 99 rotates the roll 98 about a horizontal axis in vertical alignment with the roll 91.

The rolls 91 and 98 are centered about the path P, and an upper gear sector 101 affixed to the upper motor support arm 89 meshes with a lower gear sector 102 affixed to the lower motor support arm 96. The gear sectors 101 and 102 synchronize the position of the feed rolls 9] and 98 so that both arms 89 and 95 will simultaneously pivot away from or toward the path P together.

A fluid cylinder 104 connected to the base 82 has its piston rod 105 pinned to the arm 96 to pivot same. As the piston rod 105 is extended, the feed rolls 91 and 98 will be pivoted toward the path P and as the piston rod 105 are retracted, the rolls 91 and 98 will be moved away from the path P. The cylinder 104 is connected to a conventional fluid source FS through a pressure regulator R to selectively extend and retract the piston rod 105.

Since the feed rolls 91 and 98 are identical, the same reference numerals will be applied to corresponding parts of both. Each roll includes a support cylinder 106 which is rotatably supported on the arm 89 or 96 and drivingly attached to the shaft 94 or 100. A plurality of wedge-shaped driving projections 108 are affixed to the cylinder 106 and spaced around the circumference thereof adjacent each end of the cylinder, and a plurality of driving spurs 109 are affixed about the circumference of the cylinder 106 between the projections 108. The projections 108 center the log L along the path P and, in conjunction with the spurs 109, drive the log L through the machine along the path P. The cylinder 104 maintains driving pressure between the log L and the rolls 91 and 98.

Referring to FIG. 5, it will be seen that each of the motors 92, 92, 99 and 99' are selectively connected to the ground wire 100 and the hot wire 101 through switches S2 and S3 which are positioned just forwardly of the machine and just rearwardly of the machine respectively so that when a log approaches the machine, the motors 92 and 99 will be activated by the switch S2 and when the log has cleared the machine through the feed rolls 91' and 98 on the back side thereof, the switch S3 will be deactivated to stop the feed rolls 91, 91', 98, and 98'. Since the motors 92, 92', 99 and 99 are of the constant speed type, it will be seen that the speed of the rolls 91, 91', 98, and 98 will not vary if one roll is suddenly deflected away from the log by a knot or protrusion thereon.

OPERATION In operation it will be seen that the drive motor 34 will be activated when a log L is transferred by a conveyor system CS to the machine by activating switch S2. Activation of switch S2 also starts operation of the motors 92, 92', 99.and 99. The fluid cylinders 104 and 104' cause a predetermined constant pressure to be exerting on the arms 89, 89', 95 and 95', forcing the feed rolls 91, 91, 98 and 98' toward the path P. The pump cam 58 is also pivoted into operating position through the pressure regulator 53 operatively connected to the circuit C and the solenoid 70 is also activated to accurately control the pressure in the manifold 52 and on the tools 42. y

As the conveyor system CS transfers the log L into engagement with the feed rolls 91 and 98, the protrusions 108 and spurs 109 feed rolls 91 and 98 engage the forward end of the log L and cause the feed rolls 91 and 98 to ride outwardly to the circumference of the log L and then drive the log L along the prescribed path P through the machine to be debarked. The debarking tools 42 are of conventional design and are provided with a sharpened curvilinear front edge 43 which engages the front end of the log L and causes the tools 42 to ride out to the circumference of the log L. The operating edge 47 of the tools 42 are of conventional design and operate in conventional manner to remove the bark from the log L by breaking down the cambium layer between the bark and the wood in the log L. The pressure exerted by the tools 42 is substantially constant at each particular setting of the pressure regulating assembly 61, regardless of the size log L being debarked. Therefore, logs of different sizes may be debarked without having to stop and reset the machine.

if a different species of log is to be run thereby requiring a different pressure to be exerted by the tools 42 to break down the cambium layer, this may be accomplished simply be resetting the dial D associated with the variable current device 73. This is accomplished without having to stop the machine so that different species of logs L may be debarked very efficiently.

After the log L has been debarked, it passes from the machine and clears the switch S2. This causes the switch S2 to open and stop the operation of the machine.

Although specific embodiments of the invention have been described herein, it is to be understood that full use of modifications, equivalents and substitutions may be restored to without departing from the scope of the inventive concept as set forth by the appended claims.

We claim:

1. In a log debarking machine, wherein bark is removed from a log as the log is moved along a prescribed path without appreciably turning about its longitudinal axis, of the type including:

a support member;

an annular tool holder carried by said support member for rotation about said prescribedpath; I

drive means carried by said support member for rotating said tool holder;

at least one debarking tool pivotally mounted on said tool holder for movement circumferentially about and for selectively engaging the log as the log is moved along said prescribed path to remove the bark therefrom;

the improvement which comprises:

fluid pressure means operatively connected to the debarking tool for forcing the tool into engagement with the log under substantially constant pressure regardless of the relative position of the tool with respect to the log, the tool holder and said prescribed path;

said fluid pressure means comprising:

fluid cylinder means operatively connected to the debarking tool;

fluid cylinder means carried by the tool holder and operatively connected to said fluid cylinder means to supply fluid under pressure thereto; and,

activating means carried by said support member and operatively connected to said pumping means to control the amount of fluid pumped by said pumping means to said cylinder means to selectively control the pressure of the tool against the log;

said fluid pumping means including a plunger extending from the tool holder for pumping fluid under pressure from said pumping means as said plunger is engaged by said activating means; said activating means including an 'arcuate cam pivotally mounted in said support frame at one end thereof for selectively engaging said plunger as the tool holder is rotated.

2. The apparatus of claim 1 wherein said activating means further comprises positioning means operatively connected to the other end of said cam for selectively pivoting said cam to selectively regulate the amount of activation of said plunger and thus the amount of fluid pumped by said pumping means.

3. The apparatus of claim 2 further including manifold means operationally connected to said fluid cylinder means, and check valve means operatively connecting said manifold means to said pumping means, said check valve means constructed and arranged to permit fluid flow from said pumping means to said manifold means but to prevent fluid flow from said manifold means to said pumping means.

4. The apparatus of claim 3 wherein said pressure regulating means includes a pressure release valve connected to said manifold means and constructed and arranged to selectively release fluid from said manifold at a selectively determined fluid pressure in said manifold means, and a control mechanism carried by said support member for selectively manipulating said pressure release valve to set the fluid pressure at which said pressure release valve will release fluid from said manifold means.

5. The apparatus of claim 4 further including a sliding contact connection electrically connecting said control mechanism with said pressure release valve so that said pressure release valve will rotate with said tool holder and said manifold and said control mechanism will remain stationary.

6. The apparatus of claim 5 further including means for feeding logs through said tool holder and by said debarking tool.

7. In a log debarking machine, wherein bark is removed from a log as the log is moved along a prescribed path without appreciably turning about its longitudinal axis, of the type including:

a support member;

an annular tool holder carried by said support member for rotation about said prescribed path;

drive means carried by said support member for rotating said tool holder;

at least one debarking tool pivotally mounted on said tool holder for movement circumferentially about and for selectively engaging the log as the log is moved along said prescribed path to remove the bark therefrom;

the improvement which comprises:

fluid pressure means operatively connected to the debarking tool for forcing the tool into engagement with the log under substantially constant pressure regardless of the relative position of the tool with respect to the log, the tool holder and said prescribed path;

said fluid pressure means comprising:

fluid cylinder means operatively connected to the debarking tool;

fluid pumping means carried by the tool holder and operatively connected to said fluid cylinder means to supply fluid under pressure thereto; and,

activating means carried by said support member and operatively connected to said pumping means to control the amount of fluid pumped by said pumping means to said cylinder means to selectively control the pressure of the tool against the log;

said. fluid pumping means including a plunger and,

said activating means including means for varying the stroke of the plunger, selectively, to control the amount of fluid delivered by the pumping means, thereby controlling the pressure of the tool against the log.

8. Apparatus as in claim 7 wherein the activating means includes a cam mounted in the support frame and engaging the plunger as the tool holder is rotated.

9. Apparatus as in claim 8 including means for adjusting the cam to vary the stroke of the plunger. 

